冬枣采后果皮成分及氧化酶活性变化与乙醇积累机理的研究

乙醇积累是冬枣果实贮藏期间导致变质的主要原因之一。该文研究了不同成熟度的冬枣果肉和果皮成分及氧化酶活性变化与乙醇积累的关系。试验结果表明，冬枣果实由点红转至半红、进而全红到酒软的过程中，随着成熟度的增加，果肉的多酚氧化酶(PPO)、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)的活性逐渐上升，酒化后活性都下降，并且都显著低于果皮的；而冬枣果肉的抗坏血酸氧化酶活性却显著高于果皮，并也呈逐渐增加趋势；果皮木质素和纤维素含量逐渐增加，并且显著高于果肉的，而果肉的木质素和纤维素含量变化不大。随着成熟度的增加，果肉乙醇积累增高，酒化时达最高；乙醛含量在全红时达到最高，酒化时下降。该文对果实乙醇积累与果皮木质素含量及氧化酶活性变化的相关性进行了讨论。

Changes of composition and activity of oxidative enzymes in the pericarp and mechanism of ethanol accumulation in `brumal jujube

Ethanol accumulation was one of the primary deteriorated factor of fruit during storage of `brumal jujube`. The relationship between changes of composition and activity of oxidative enzymes in the flesh and pericarp and ethanol accumulation in different maturity of `brumal jujube` were investigated. The results show that ascorbic acid oxidase activity in the flesh of `brumal jujube` is significantly higher than that in pericarp with the development of maturity; but these activities of peroxidase, polyphenoloxidase and phenylalanine ammonia lyase in flesh are lower than those in pericarp. During the development from green to half red then to red, the lignin and fibre content in pericarp gradually increase, higher than those in flesh; ethanol content also increases, acetaldehyde content reaches a peak during the red maturity stage and then declines. The relationships between ethanol accumulation, lignin content and the activity of oxidase during the ripening of `brumal jujube` are discussed.